TON Network’s Struggles: The Recent Block Generation Halts and Underlying Design Challenges

TON Network’s Struggles: The Recent Block Generation Halts and Underlying Design Challenges

In August, the TON Network faced a series of disruptions that put the spotlight on its infrastructure and overall future as a blockchain platform. These incidents coincided with the arrest of Telegram’s founder, Pavel Durov, in France, sparking further controversy and uncertainty for TON. While much of the media attention focused on Durov’s legal issues, the technical failure of the TON Network presents a more significant challenge to its future.

The TON Network’s inability to generate blocks twice within a short span of time points to underlying problems in its design and operation. This analysis explores the reasons behind these disruptions, looking into the TON white paper, technical documents, and current network performance to uncover the core issues.

Recap of the Events: Two Block Generation Halts in Two Days

On August 28, 2024, the TON Network experienced its first block generation halt, lasting seven hours before block production resumed. Less than 24 hours later, on August 29, a second block generation halt occurred in the early hours of the morning, further raising concerns about the network’s stability.

Immediate Cause: DOGS Token Transaction Overload

The immediate reason for the block generation halts was a massive increase in transaction volume related to the DOGS token. DOGS is a meme token on the TON Network, with a total supply of 5.5 trillion tokens, of which 72.73% were distributed through an airdrop that required only a Telegram account to participate. With DOGS being listed on major platforms like Binance, the TON Network saw an enormous surge in transactions within a short period.

As a Proof-of-Stake (PoS) blockchain, TON relies on validator nodes to process and confirm transactions, which are then packaged into blocks. Typically, a blockchain network is designed to generate new blocks at regular intervals, but when the system becomes overwhelmed by pending transactions, block generation can slow down or even stop altogether.

Transaction overload is not unique to TON; even large networks like Bitcoin and Ethereum have faced similar challenges in the past. When the transaction volume exceeds a network’s processing capacity, validation speeds drop significantly. In the case of TON, the sudden surge in DOGS transactions likely overwhelmed validator nodes, slowing block generation to the point of complete halt.

Surface Explanation from the TON Foundation

The TON Foundation explained that the halt occurred because DOGS transactions overloaded the network, triggering garbage collection processes that overloaded many validators, leading them to lose consensus. However, this explanation raises further questions. In November 2023, TON had set a Guinness World Record for achieving 104,715 transactions per second (TPS) during a public performance test. Given this, the explanation that DOGS transaction overload caused the halt seems inadequate, pointing to deeper issues within the TON Network’s infrastructure.

Deeper Causes: Structural and Validator Challenges in TON

While transaction overload was the proximate cause of the block halts, the root of the problem lies in the design of the TON Network and its validator mechanisms. A detailed analysis of TON’s technical architecture, sharding mechanism, and validator organization reveals several key factors that contributed to the instability during high transaction volume.

1. Complexity of the Sharding Architecture: Challenges of High Scalability

The TON Network’s architecture is designed for high scalability and performance, with a unique multi-layer structure consisting of the masterchain, workchains, and shardchains. This setup theoretically allows TON to distribute transaction loads across multiple chains, significantly increasing processing capacity.

Each workchain can be further subdivided into several shardchains, with each shardchain responsible for processing transactions for specific accounts. This design allows for parallel processing of transactions across shardchains, theoretically boosting the network’s overall TPS.

However, this complex sharding structure also introduces challenges. When transaction volumes surge, as was the case with DOGS, uneven load distribution or validators failing to process large volumes can cause the shardchain’s block production to slow down or halt. Since shardchains must remain synchronized with the masterchain, any critical disruption in one shardchain can have ripple effects across the entire network, potentially halting block production.

TON’s sharding approach is highly innovative, allowing shardchains to be minimized to the point where each shard handles transactions for only a small number of accounts or even a single smart contract. However, this extreme level of sharding also increases the complexity of coordination and management between shardchains and the masterchain.

While sharding is an effective means of improving scalability in blockchain networks, it requires a high degree of coordination between shardchains and the masterchain. In cases of extreme transaction overload, if a key shardchain bottlenecks, the entire block generation process can be disrupted, as seen during the DOGS incident.

2. Insufficient Validator Numbers: A Risk to Decentralization and Performance

Another significant issue within the TON Network is the insufficient number of validators. Compared to other PoS blockchains, the number of validators on TON is relatively low. As of 2024, the TON Network operates with only 360 validator nodes, a number that pales in comparison to Ethereum’s 1 million validators or Solana’s more robust validator set.

In PoS networks, validators are responsible for verifying transactions, achieving consensus, and packaging transactions into blocks. The number of validators not only determines the decentralization of the network but also directly impacts its capacity to handle high transaction loads. Fewer validators mean that each node must process more transaction requests. When transaction volumes surge, such as during the DOGS incident, validators may be unable to process all transactions in time, causing delays or block generation halts.

Moreover, TON imposes strict hardware and network requirements on validators, with a high Toncoin staking threshold required to become a validator. These barriers to entry limit the number of participants who can join the validator set, leading to an underdeveloped validator network.

The low validator count limits TON’s decentralization and increases the likelihood of block production delays, especially during periods of high transaction volume.

3. Consensus Mechanism Limitations: Challenges of the Byzantine Fault Tolerance Protocol Under High Load

TON employs a Byzantine Fault Tolerance (BFT) consensus mechanism, specifically the Catchain protocol. This protocol is designed to ensure that the network continues to function even in the presence of malicious nodes. However, when the number of validators is limited and some validators fail to participate due to transaction overload, the efficiency of the BFT consensus mechanism decreases.

The Catchain protocol operates by ensuring consensus among validators as long as fewer than one-third of them are malicious. However, under high transaction loads, if multiple validators are unable to respond in time, the consensus process can slow down or fail to reach an agreement, halting block generation altogether.

While TON’s consensus mechanism is robust in theory, its practical effectiveness is heavily reliant on the number and availability of validators. During the DOGS overload, the limited validator set and their inability to keep up with the transaction volume likely exacerbated the inefficiencies of the Catchain protocol, leading to block production stoppages.

Limitations in Decentralization and Infrastructure: Roadblocks for TON’s Future

The TON Network faces several significant challenges in both its external and internal landscapes. The recent arrest of Telegram’s founder creates legal and operational uncertainties that could affect future collaborations between Telegram and TON. With Telegram’s 1 billion monthly active users being viewed as a key asset for TON’s growth, this incident casts a shadow over potential integration.

Internally, TON’s repeated block generation halts in a short span of time expose the limitations of its current infrastructure. Although the overload caused by DOGS was the immediate trigger, the deeper issues lie in the complexity of the sharding architecture, insufficient validator numbers, and the limitations of the consensus mechanism under high load conditions. These factors point to significant design challenges that TON must address if it is to ensure the stability and sustainability of its network.

Recommendations for TON’s Future Stability and Growth

For TON to overcome its current challenges and ensure its long-term growth, the network needs to focus on several key areas of improvement:

  1. Expand Validator Numbers: TON should reduce the barriers to entry for validators by lowering the staking requirements and hardware demands. By expanding the validator set, TON can improve its decentralization and increase the network’s capacity to handle high transaction volumes.
  2. Optimize Sharding Architecture: TON must refine its sharding architecture to enhance the efficiency of coordination between shardchains and the masterchain. Ensuring smooth communication and synchronization between chains will help prevent future block generation halts during periods of high transaction activity.
  3. Further Develop the Consensus Mechanism: While TON’s Catchain protocol is robust, it needs to be optimized for high-load scenarios. Research into improving its efficiency under extreme conditions will help maintain block production stability during peak transaction periods.

Conclusion

TON has faced significant challenges since its inception, but the recent block generation halts highlight some of the most critical structural issues in its network. The DOGS transaction overload revealed deeper problems in TON’s sharding, validator, and consensus mechanisms that must be addressed to ensure future growth. While these incidents do not pose an existential threat to TON, they underscore the need for immediate improvements to safeguard the network’s stability and ensure its place in the rapidly evolving blockchain ecosystem.